Today, we can enjoy music recorded in various recording formats (i.e., music recorded from various sources). Such music includes, e.g., music based on an analog sound source such as AM or FM radio, music based on a digital sound source such as CD or DVD, and the like.
A typical audio device includes an operation section (selector or touch panel) for selecting various sources. A listener operates the operation section to select one of the sources so as to reproduce his or her favorite music (refer to Patent Document 1).